Change 742427 had a related patch set uploaded (by Thiemo Kreuz (WMDE); author: Thiemo Kreuz (WMDE)):

[mediawiki/extensions/TemplateData@master] Fix serialization adding empty autovalue when not needed

https://gerrit.wikimedia.org/r/742427

Change 742427 merged by jenkins-bot:

[mediawiki/extensions/TemplateData@master] Fix serialization adding empty autovalue when not needed

https://gerrit.wikimedia.org/r/742427

Failed during demo, the empty autovalue block was still added.

Are you sure? For me it works as intended on the Beta cluster.

Yes, I tried locally and on the beta cluster. Steps to reproduce:

• Open https://en.wikipedia.beta.wmflabs.org/wiki/Template:Test for editing
• Click "Manage TemplateData"
• Open the first parameter
• Set an autovalue
• Apply changes (don't save the page)
• Open again
• Clear the autovalue
• Apply changes (don't save)

What should happen: no autovalue should be present

What actually happens: the parameter has autovalue: "".

Note that we discussed during sprint review and work on this ticket shouldn't continue until we can discuss with the Product side.

In T295074#7596744, @thiemowmde wrote:

I think when you say "apply" you close the TemplateData editor. This persists what was done in the editor and adds "autovalue": "foo" to the page's wikitext. The dialog will never remove an existing field like this, even if it's emptied.

Are you sure? When I clear an existing "default" value, the property disappears from the JSON.

Oh. I got confused because this ticket here is not about the default. I created T298607: Some values are removed from the JSON when emptied, some aren't for the issue you described.